Work-clamp-positioning device



E. B. ALLEN WORK GLAMP POSITIONING DEVICE Filed Dec 29 1932' 4 Sheets-Sheet 1 NVENTOR VATTORNEY April 8, 1924,

E. a. ALLEN WORK' CLAMP POSITIONING DEVICE Filed Dec. 29 1922 4 Sheets-Sheet 5 INVENTOR ATTORNEY WITNESSES:

April 8, 1924. 1,489,299

E. B. ALLEN WORK CLAMP POSITIONING DEVICE 4 Sheets-Sheet 4'.

Filed Dec. 2.9. 1922 INVENTOR ATTORNEY Patented Apr. 8. 1924..

ITED STATES PATENT OFFICE.

EDW'ARD B. ALLEN, OE NE'WT'DWN, CONNEGTZCUT, ASSIGNOR TO THE SINGER MANU- FACTUBING COMPANY, JERSEY.

O}? ELIZABETH, NEW JERSEY, A CORPORATION OF NEW WORK-CLAMP-POSITIONING DEVICE.

Application filed December 29, 1922.

T 0 all whom/2'1? may concern:

Be it known that I, EDWARD B. ALLEN, a citizen of the United States, residing at Newtown, in the county of Fairfield and State of Connecticut, have invented certain new and useful Improvements in Work- Clamp-Positioning Devices, of which the followin is a specification, reference being had therein to the accompanying drawings.

This invention relates to buttonhole sew ing machines of the type having stitchforming mechanism and a work-clamp with means for relatively moving them to sew around a buttonhole. Some machines of this type employ a buttonhole cutter which is operated to cut the buttonhole prior to sewing, in which case means are usually provided for spreading the work-clamp to open up the buttonhole-slit for passage of the needle making the overedge stitch. In other machines, the work-clamp is operated to spread the work prior to sewing but the buttonhole cutter is operated to cut the buttonhole after the sewing operation. It will be appreciated that, in all buttonhole sewing machines wherein sewing and slit-cutting mechanisms operate at difierent times upon the work, nice registering of the workclamp with the sewing and cutting mechanisms is essential to the production of acceptable work. I

Heretofore, the feed-cam connections for moving the work-clamp have usually been depended upon to hold the work-clamp in position during the action of the buttonhole cutting and clamp-spreading mechanisms, and it has been found that imperfect work is sometimes produced because of the inaccurate registering of the w0rkclamp and the buttonhole-cutter. It has also been noticed that, when handling heavy work, there is a tendency for the clamp-spreading devices to displace or distort the workclamp mechanism.

The present invention has for an object to provide a buttonhole sewing machine with means for insuring that the work-clamp and b-uttonhole cutter will be in register when the buttonhole is out.

Another object of the invention is to overcome the tendency of the work-clamp mechanism to become displaced or distorted in the operation on heavy work.-'

Serial No. 609,575.

Further objects of the invention will appear from the following description and claims.

To the accomplishment of the ends in View, there is provided mechanism, in addition to the usual feeding means, for registering the work-clamp and buttonhole cutter during the buttonhole cutting operation. The novel means herein provided is preferably constructed in the form of an interlocking connection between the Workclamp and the butto'nhole-cutter for relatively fixing or registering these parts dur ing the buttonhole cutting operation. The interlocking connection is preferably afforded by providing the work-clamp carrier-plate with a slot restricted in width to closely fit a movable element of the buttonholecutter such, for example, as the usual travelling buttonhole-cutter fulcrum-block. \Vhen the buttonhole-cutter is moved to cut the buttonhole, the fulcrum-block, functioning as the bolt of a lock, enters the slot in the clamp-carrier plate and registers the tmttonholecutter and work-clamp; at the same time looking the work-clamp against sidewise movement. \Vhen the buttonhole cutter is retracted, the fulcrum-block is withdrawn from the slot in the clamp-carrier plate and the latter is unlocked for the usual feeding movements. In the present machine the clamp-spreading mechanism is preferably timed to operate while the cutter fulcrum-block is in the slot of the clampcarrier-plate and the latter is thereby greatly stiffened and prevented from being shifted or sprung laterally under reactionary strains produced by the operation of the clamp-spreading mechanism; these strains being usually more severe when operating upon heavy work.

In the accompanying drawings Fig. l is a horizontal section through the bracketarm standard of a buttonhole sewing machine embodying the invention, showing the work-clamp and machine bed in plan. Fig. 2 is a fragmentary plan View of the machine bed with the rearward portions of the separable work-clamping elements broken away. Fig. 3 is a fragmentary side elevation of thebuttonhol cutting mechanism, clamp spreading mechanism and thecertain elements of work-clamping mechanism.

cutter in end elevation.

Fig. 4 is a fragmentary lan View of the machine bed showing the longitudinal slide frame and the cross-slide-plate which carries the work-clamping elements or plates; the latter having been removed. Fig. 5 is a plan View of the clamp-spreading toggle mechanism and its carrier-plate. Fig. 6 is a side elevation of the buttonhole cutting mechanism. Fig. 7 is a section on the line 7-7, Fig. 5. Fig. 8 is a fragmentary transverse vertical section through the machine bed and work-clamp, showing the buttonhole Fig. 9 is a fragmentary bottom plan view of the crossslide-plate which carries the separable workclamping members. Fig. 10 is an elevation of the toggle mechanism shown in Fig.

Fig. 11 is an enlarged plan view of the wearlugs which are attached to the cross-slideplate element of the work-clamp mechanism,

and Fig. 12 is a rear elevation of one of the work-clamp-lever fulcrum-blocks.

In the preferred embodiment of the invention, as illustrated 1 represents the bed and 2 the bracket-arm standard of a buttonv hole sewing machine such as disclosed. in my copending application Serial No. 537,381, filed Feb. 18, 1922. This machine embodies the usual stitch-forming mechanism represented by the needle 3, Fig. 3, and needle-throat 4, operating at afixed location relative to the bed 1.

The work-clamp of the particular machine illustrated is movably mounted on the bed 1 and comprises the usual laterally separable lower work-supporting plates 5, 5,

and upper clamping feet 6, 6 pivotally car ried at the forward ends of the clamping levers 7, 7 which at their rearward ends are fulcrumed between the parallel upstanding plates 8. 8. Fig. 8, of the clamp-lever fulcrum blocks 9, 9 mounted respectively on the separable work-supporting plates 5. When the machine is started, the clamps are closed by the downward movement of a clamprlosing lever 10, Fig. 1. having a roller 11 at its free end which depresses an arm 12 fixed to one of the separably connected rock-shaft sections 13, 13 journaled at the forward ends of the plates 8, 8 of the clamplcver fulcrum blocks. The rock-shaft sections 13 13 carry cams A, 14- which depress the clamp-levers 7, 7 to work-clamping position, Fig. 3. The fulcrum-supports for the upper clamping levers 7 each comprise a block 7% Fig. 12, fulcrunied between the upstanding A plates 8 by means of fulcrum screw-studs 7 Fixed vertically in the block 7 and extending above the latter is the screw-pin 7 carrying the thumb-nut 7 The thumb-nut T has an upper flange 7 and lower flange 7 connected by a reduced neck 7 which passes through the slot 7 extending longitudinally of the clamping lever '7 at the rear inseczee end of the latter. A plate 7 is superposed upon the lever and has a slot "P out transversely through one edge of said plate 7 to admit the neck 7 of the thumb-nut 7. The slate 7 formed with longitudinal slot '7 thrcus 'h which passes a screw 7 threaded into the le 7. B r turning the thumb-nuts 7 the worn clamp levers 7 may be quickly adjusted to accommodate work of any thickness and loosening the sore-vs 7" the levers may be adjusted longitudinally of their fulcra 7 to longitudinally register the clamping t 6 and plates 5, after which the screws '7 are tightened.

The separable work-clamping plates are superposed upon and carried by the crosse 15, the rearward half of which rests upon the bed i, as shown in The cross-slid.eplate 15 is ont end with depending lugs are apertured to slidably fit ss-slide-rod 1?, connecting the side members 18, 18 of the lit e-fraine the rearward are provided their forward ends with flattened depending pins 21, 21, Figs. 1 and which are detachahly received the n-sided apertures 22, 22 at the front ends the forward clamp-spreading levers 23, 23 pivotally mounted. at 24%, 24 on the under side of the cross-slide-plate 15. Clampspreading movements are imparted to the levers by means of the link 25 which extends etwcen the levers 23 and is formed i h e. e surfaces 26 coacting with foliloclrs 27 secured to the levers 23 and 1 able crosswise of the latter by means of screw and slot connections 28. A spring 539 anchored its opposite ends to pins 30 separable work-clamping members on the respective levers 23. holds the latter itrict with the link 25. The link 25 deits clampspreading and unspreading f om the mechanism which spreads the ard ends of the separable workclamping members and which will now be described.

tilidably resting upcn the plate 19 of the longitudinal slide-frame and screwed to the cross-slide-plate 15 at 31, 31 by screws 3:2, 32 is the toggle plate 33 having transverse guideways 84;, Fig. 5, for the slideblocks 35. Pivoted centrally of the plate 83' is the lever 36 which is connected at its opposite ends by pivot pins 37. 38 to the links 39. 40. the latter being pivotally connected to the slide-blocks 35. The lever 36 and links 39. 4:0 constitute a toggle device which, when straightened, imparts outward or their opposite ends.

clamp-spreading movements to the slide blocks 35. The blocks 35 carry upstanding pins ll which impart the clamp-spreading movements of the blocks to abutment screws 42, 42, Fig. 1, carried respectively by the outer side members 8 of the clamp-lever fulcrum-blocks 9 mounted on the separable lower clamp-plates 5. The pivot pin 37 has a downward extension 43, Fig. 7, which enters the apertured rear endof the link 25, thus connecting the clamp-spreading levers Q3 and slide-blocks 35 for simultaneous clampsprcading movements. he parts are preferably so adjusted that these movements are of equal amplitude, whereby the clamp-plates are spread equal distances at One of the slide-blocks 35 has pivotally mounted thereon at n the lever 4C5 having a forked extremity -16 embracing the pivot pin 37. It will be clear that when the outer end of the lever 45 is moved forwardly or to the left, Fig. 1, the clamp-plates 5 will be spread, and vice versa.

The clamp-spreading mechanism is actuated from a cam 47 on the well known cutter-shatt 48 which at an appropriate time is driven for one revolution only through the usual one-rotation clutch-connection 4:9 with the continuously running cutter-actuating pulley 50. The cam 417, Fig. '3, swings the T lever 51 about its fulcrum (not shown) at the bottom of its upright leg and causes its forwardly extending arm 52 to push the lever 4:5 to clamp-spreading position.

The means for relatively moving the stitch-forming mechanism and work-clamp to sew around a buttonhole preferably comprises the usual feed-wheel 53 having in its upper face the longitudinal feed-groove 54 and lateral feed-groove 55. The longitudi nal feedgroove 54 is entered by the tollower 56 on the lever 57 fulorumed at 58 on the bed 1. and connected by the link 59 to the longitudinal slide-frame A. The lat eral feed-groove is entered by the fol lower 60 carried by the lever 61 which is coupled at 62 to the rearward arm 63 of a lever fulcrumed at 64: on the bed 1; the forward arm 65 of said lever having a sliding connection 66 with the slideway 67 carried on the under side of the cross-slideplate 15.

The buttonhole cutting mechanism preferably comprises the cutter-levers 68. 69 which are fulcrumed at 70 on the travelling fulcrum block 71 slidable longitudinally of the bed 1 in ways 72 Fig. 8, formed in the said bed. The cutter-levers are given their closing movements by means of the usual cutter-closing cams 73, 74 on the cuttershaft 48. The cutter advancing and -retracting movements are derived from a cam 7 5 which is fixed on the cuttershaft 48 and operates through a follower link 76 con nected to a rearward extension 7 7 of the cutter-lever fulcrum block 71. y a

The constructive features of the machine above described, as well as associated features not herein specifically referred to, are substantially in accordance with the disclosure of my said copending application and my Patent No. 15,324, reissued April at, 1922, to which reference may be had for a more complete description of the machine.

With the foregoing as a basis the constructive features ofthe present improve ment, in its preferred embodiment, will now be set forth.

Heretotore, in most cases, the feed-cam and its lateral-feed connections have been depended upon to laterally fix the workclamp in buttonhole cutting position. 'Wear in these connections will in time result in lost motion and in inaccurate positioning of the worlnclamp for the cutter. I now preferably provide a direct interlocking connection between the work-clamp and buttonhole cutter to insure that these parts will be in register when the buttonhole is cut. So far as I am aware, this interlocking connection is broadly new in a buttonhole sewing machine.

In my prior constructions the cross-slideplate of the work-clamp was commonly provided with a longitudinally extending clearance slot for the cutter-lever fulcrumblocilr. This slot was. throughout itslength, broader than said fulcrum block andthe side walls of such slot did not engage the cutter fulcrum block at any time in the cycle of operations. When the buttonhole cutting mechanism was operated the lateralfeed connections with the feed-wheel were depended upon to laterally locate the workclamp in cutting position.

In the embodiment of the invention illustrated. means are provided for reducing the width of a portion of the cutter-clearance slot in the cross-slide-plate so that the side walls of such slot will be engaged by the cutter fulcrum-block when the latter is advanced to cutting position. Thisresult may be attained, for example, by mounting hardened wear plates 78 on the opposite side faces of the cutter-lever fulcrum-block for cooperation with the hardened wear lugs 79 secured to the cross-slide-plate 15. The wear lugs 79 reduce the width of a portion of the slot in the cross-slide-plate15 and have beveled corners 80 to relatively guide the fulcrum-block 71 and cross-slide-plate 15 into interlocking relation; the fulcrumbloclr 71 operating as the bolt of a lock.

When the machine is to be operated the operator presses the usual starting button which trips the clamp-closing mechanism into operation. Afterthe clamps are closed the clamp-closing mechanism trips the onerotation clutch device 49 and effects the couplingof the cutter shaft 48 to the continuously rotating pulley 50 for one revolution during which the cutter-levers are advanced from their retracted or inoperative position, Fig. 4, to cutting position, Fig. 2. The advance of the cutter-levers carries the wearplates 78 forwardly into engagement with the wear-lugs 79 and locks the cross-slideplate in a fixed lateral position relative to the buttonhole cutting mechanism and the machine frame. After the buttonhole has been cut and while the cutter-levers are being retracted, the cam 47, Fig. 3, acts through the lever 51 to spread the workclamp. Fig. 3 illustrates the relative positions of the parts when the clamp-spreading lever 51 occupies its extreme forward position, i. e., when the clamps are fully spread, and it will be seen that the rearwardly moving wear-plates 78 are still in engagement with the Wear-lugs 79 and prevent side twisting or shifting of the cross-slide-plate 15 under the reactionary strains produced by the forward pressure of the lever 51 upon the lever 45 of the clamp-spreading toggle mechanism. Except for the interlocking connection herein provided, there would be a tendencv for the cross-slide-plate 15 to spring sideways about its front end supporting means 16, 17 as a fulcrum, under the reactionary strains. produced by the clampspreading lever 51. These strains acting through the cross-slide-plate 15 would also tend to distort the longitudinal slide frame 18, 17, 18, 19 from rectangular to rhomboidal form. By the use of the present interlocking connection the distortion of the crossslide-plate 15 and longitudinal slide frame A is prevented, even under the severe strains encountered when operating on heavy overcoats and the like.

While I have disclosed the invention as embodied in a buttonhole sewing machine of the type illustrated in my said prior patent and copending application, it will be recognized by those skilled in the art as being applicable in its broader aspects to buttonhole sewing machines of various types;

' not being limited to machines in which the relative movement between the stitch-form-' ing mechanism and work-clamp is produced by moving the work-clamp.

Having thus set forth the nature of the invention, what I claim herein is 2- 1. A buttonhole sewing machine having, incombination, stitch-forming mechanism, a work-clamp, means for relatively moving and positioning the stitch forming mechanism and work-clamp to sew around a buttonhole, a buttonhole cutter, and means for locking the work-clamp and buttonhole cutter against relative lateral displacement during the buttonhole cutting operation.

2. A buttonhole sewing machine having,

first-mentioned means, for laterally fixing.

said work-clamp relative to the'machine frame durin the operation of the buttonhole cutting mechanism.

4:. A buttonhole sewing machine having, in combination, a frame, stitch-forming mechanism, a work-clamp, means for relatively moving and positioning the stitchforming mechanism and work-clamp to sew around i a buttonhole, clamp-spreadin means, and locking means independent 0 said first-mentioned means, for laterally fixing said work-clamp relative to the machine frame during the operation of the clampspreading mechanism.

5. A buttonhole sewing machine having, in combination, a frame, stitch-forming mechanism, a work-clamp, feeding means for moving the work-clamp to sew around a buttonhole, clamp-spreading mechanism, and means for locking the work-clamp to the machine frame during the operation of the clamp-spreading mechanism and foruIllocking the work-clamp for the sewing operation.

6. A buttonhole sewing machine having in combination, stitch-forming mechanism, a work-clamp. means. for relatively moving and positioning the stitch-forming mechanism and work-clamp to sew around a buttonhole, buttonhole cutting mechanism, and a slot and bolt connection for relatively locking the work-clamp and buttonhole cutting mechanism during the buttonhole cutting operation.

7. A buttonhole sewing-machine having in combination, stitch forming mechanism, a work-clamp, means for relatively moving and positioning the stitch-forming mechanism and work-clamp to sew around a buttonhole, buttonhole cutting mechanism, a slot and bolt connection between the workclampand buttonhole-cutter, and means for operating said connection before and after the buttonhole is cut to relatively lock the work-clamp and buttonhole cutter during the cutting operation and to unlock them after the buttonhole has been cut. 7

8. A buttonhole sewing machine having,

"in-semen nism and work-c1amp to sew around a but-- tonhole, a buttonhole-cutter, and a buttonhole-entter and Work-clamp interlock com prising interlocking elements Which are out of engagement with one another during the sewing, and means for moving them into interlocking relation during the buttonhole cutting operation.

In testimony whereof, I have signed my name to this specification.

EDWARD B. ALLEN. 

